(a) Field of the Invention
This invention relates to a high thermal change rate test device, and more particularly to the following: (1) In response to test form requirements, mobility is high, there is great of flexibility shakers, and more usage. (2). Liquid nitrogen enters the chamber via multiple pipes. Electric heaters are also divided into two groups for control, and to achieve the effects of a rapid rise and fall of temperature, and constant temperature stability. (3). The dispersion effect of spray ejected from liquid nitrogen nozzles is good, and it has a good temperature reduction efficiency and temperature distributing effect when used in the temperature cabinet. (4). Suitable pressure of liquid nitrogen pipes can be adjusted to satisfy cooling rate requirements, and prevent excessive pressure to cryogenic valves lead to loss of control and cause excessively low temperature.
(b) Description of the Prior Art
In a conventional temperature test apparatus for conducting Highly Accelerated Life Test (HALT) or Highly Accelerated Stress Screening (HASS) of electronic hardware, the form of assembly and the matching shaker are almost fixed. The mobility and form of test assembly has little flexibility. The precision of temperature control of liquid nitrogen used is not satisfactory. In addition if achieving a high temperature change rate for a conventional compressor refrigerating system is required, the cost is high, the mobility and assembly flexibility are low, the rate of breakdown after long-term use is high, and maintenance is not easy.